Grass treatment machines are used for treating grass surfaces such as lawns, golf courses, playing fields and parkland. Various types of grass treatment machines exist and include, but are not limited to, mowers, rollers, scarifiers and spikers. As is known to those skilled in the art typically such machines include one or more grass treatment devices or heads, each device comprising one or a plurality of grass treatment tools or elements. For many prior art grass treatment machines, such as, for example, those manufactured by John Deere, Toro, or Jacobsen, a plurality of grass treatment devices (typically two or three) are mounted on a given machine. A common configuration of three such grass treatment devices is such that they are mounted in a reverse echelon disposition: two grass treatment devices are mounted at the front of the machine with the third being mounted substantially immediately behind the first two.
Those skilled in the art will understand that in recent years improved varieties of grass have been bred for use as sports surfaces. In particular improved varieties of grass have been specifically bred for use on fairways and/or putting greens of golf courses and it is known that these grasses have become increasingly dense growing in comparison to earlier forms of grass. In relation to the improved grasses, generally known as ultra dense dwarf grasses, this means that the number of grass shoots per unit area is greater than with previous types of grass. Ultra dense dwarf grasses allow the grass to be cut to very low heights, which in turn allows greens and fairways to be faster, as regards the speed of travel of a golf ball disposed thereon, than has ever been previously possible. Examples of these new high-density grasses include cultivars of Bermuda Grass and Creeping Bent. As will be understood by those skilled in the art the aforementioned advanced grass surfaces require evermore increasing accuracy and care in their treatment and in particular in their being cut.
It is often necessary to adjust the height of a grass cutter or other treatment device on an ad hoc basis, as localised conditions require. This is because a grass or turf surface may be uneven or contoured. A common problem that may arise is that due to the use of an improperly adjusted grass cutter element. By improperly adjusted it is meant herein that either the cutter is set too high or too low for cropping of a given grass surface. A particularly undesirable is where the grass is cut too low resulting in so-called ‘scalping’ of the grassed surface. In relation to grassed surfaces for use in the sport of golf this means the removal of the entirety of the grass from an area. This frequently results in serious problems for golf players wishing to use the surface and generally renders the surface unusable. Less drastically, problems resulting from uneven cutting or treatment can also make a surface unplayable as such uneven treatment can make surfaces unpredictable and therefore undesirable to play upon.
As is known to those skilled in the art grass treatment devices typically comprise a number of rotational elements. Known prior art devices typically comprise front and rear rolling elements or rollers and positioned there-between are one or more grass treatment elements (or tools) of one kind or another. Commonly the treatment tool or tools provided include a grass cutting tool and/or a grooming tool, a grooming tool being a tool to lift the blades of grass into a substantially vertical direction ready for cutting. However another commonly employed tool is a grass treatment brush provided to attempt to remove debris from the densely packed grass. The height of the treatment tools require careful adjustment so as to accurately set their operating height above ground level. Prior art adjustment mechanisms operate in part by adjusting the distance between the first and/or second roller and the grass treatment tool. A disadvantage of such a mechanism is that in general adjustments need to be made to both sides of one or both rollers so as to provide an even adjustment to the overall device and ensure a uniform cut height of the grass.
As indicated above it is necessary to adjust the height of the grass treatment tool associated with the grass treatment device on an ad hoc basis, as it may be necessary both to make a number of different height cuts on different portions of a single surface or more normally different portions of an overall venue. Further problems associated with the necessity to make such adjustments using the prior art mechanism are that requiring two separate adjustments to be made at either side of the roller means that an unskilled or unobservant operator of such a prior art grass treatment device can inadvertently set the relative height on both sides of the adjustment mechanism to different levels and thereby cause uneven grass treatment levels. For instance if grass cut height varies along the length of the grass treatment tool then the effect will spread over the entirety of a grass surface that is being treated. Such differential treatment regimes can have serious implications as to the viability and properties of any grass surface so mistreated.
In view of the above there is a need to provide an improved height adjustment mechanism for grass treatment devices such that treatment elements (including, for example, cutters, groomers and brushes) are more accurately and reliably set before and during use of a given grass treatment apparatus.